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Kusuri Formalin 30% is best used with Kusuri Malachite Green for the effective treatment of most single-cell parasites including White Spot, Costia, Chilodonella, Oodinium and Protozoan Parasites.


Use above 12.5°C (54.5°F) 


Kusuri does not recommend the use of Formalin with any salt solution.


Please ensure that you read, understand and follow all Health and Safety guidelines on the bottle.


Please do not eat, drink or smoke whilst handling chemicals.


Wear disposable vinyl or latex gloves and appropriate eye protection.


Dosage: 75ml per 1000 gallons (4546 Litres) of pond water.


For our handy dosage calculator, click here!


For use above 12.5°C (54.5°F)



  • The normal course is 3 treatments, 5-7 days apart.
  • Switch off UV steriliser until course of treatment is complete.
  • Formalin is a very active chemical and is best used with Kusuri Malachite Green.
  • Slowly apply to the pond over a 1 hour period; this will prevent shocking the pond with a highly concentrated dose.


Formalin is highly toxic and a carcinogenic chemical, please ensure you read, understand and follow, all safety guidelines included with this product.


Do not use Malachite and Formalin in conjunction with salt.

Kusuri Formalin

SKU: MD914
PriceFrom £14.00
  • Collection from our premises near Chepstow in South Wales by appointment or delivery to British mainland addresses.


    Delivery is £8.95 per order for most dry goods, with some more expensive delivery charges applicable for very heavy or long items.


    Please note delivery for dry goods is typically 2-5 working days and items may be sent in separate packages.

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